Preheat your oven to 425.
Mix together your crumble topping ingredients in a bowl and combine with a fork. Set aside.
In a separate bowl, mix together your dry ingredients for your muffins and then whisk to combine well.
In another large bowl, mix together the wet ingredients for the muffins. You can either use softened butter of melted butter but make sure the butter isn't hot.
Slowly begin mixing in your dry ingredients for the muffins into the wet ingredients. Do a little at a time and then blend in between.
Fold in your apples.
Line your muffin tins and then fill them almost all the way to the top.
Sprinkle the crumble on heavily.
Bake for 18-20 minutes.
While the muffins are baking, combine the milk and powdered sugar in a bowl and whisk. Set aside until the muffins are done.
Once the muffins are baked wait about 10 minutes to cool and then add the glaze. Serve immediately or save in an airtight container for up to 48 hours.